diff --git a/src/test/key_tests.cpp b/src/test/key_tests.cpp
--- a/src/test/key_tests.cpp
+++ b/src/test/key_tests.cpp
@@ -46,7 +46,7 @@
         assert(sigECDSA[4] == 0);
         std::copy(sigECDSA.begin() + 5, sigECDSA.begin() + 37, ret.begin());
     } else {
-        std::copy(sigECDSA.begin() + 4, sigECDSA.begin() + 36,
+        std::copy(sigECDSA.begin() + 4, sigECDSA.begin() + (4 + rlen),
                   ret.begin() + (32 - rlen));
     }
     return ret;